/*
Kooboo is a content management system based on ASP.NET MVC framework. Copyright 2009 Yardi Technology Limited.
This program is free software: you can redistribute it and/or modify it under the terms of the
GNU General Public License version 3 as published by the Free Software Foundation.
This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along with this program.
If not, see http://www.kooboo.com/gpl3/.
*/
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Linq.Expressions;
namespace Everest.Library.Data.Entity{
internal abstract class ExpressionVisitor {
protected ExpressionVisitor() {
}
[System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Maintainability", "CA1502:AvoidExcessiveComplexity")]
protected virtual Expression Visit(Expression exp) {
if (exp == null)
return exp;
switch (exp.NodeType) {
case ExpressionType.Negate:
case ExpressionType.NegateChecked:
case ExpressionType.Not:
case ExpressionType.Convert:
case ExpressionType.ConvertChecked:
case ExpressionType.ArrayLength:
case ExpressionType.Quote:
case ExpressionType.TypeAs:
return this.VisitUnary((UnaryExpression)exp);
case ExpressionType.Add:
case ExpressionType.AddChecked:
case ExpressionType.Subtract:
case ExpressionType.SubtractChecked:
case ExpressionType.Multiply:
case ExpressionType.MultiplyChecked:
case ExpressionType.Divide:
case ExpressionType.Modulo:
case ExpressionType.And:
case ExpressionType.AndAlso:
case ExpressionType.Or:
case ExpressionType.OrElse:
case ExpressionType.LessThan:
case ExpressionType.LessThanOrEqual:
case ExpressionType.GreaterThan:
case ExpressionType.GreaterThanOrEqual:
case ExpressionType.Equal:
case ExpressionType.NotEqual:
case ExpressionType.Coalesce:
case ExpressionType.ArrayIndex:
case ExpressionType.RightShift:
case ExpressionType.LeftShift:
case ExpressionType.ExclusiveOr:
return this.VisitBinary((BinaryExpression)exp);
case ExpressionType.TypeIs:
return this.VisitTypeIs((TypeBinaryExpression)exp);
case ExpressionType.Conditional:
return this.VisitConditional((ConditionalExpression)exp);
case ExpressionType.Constant:
return this.VisitConstant((ConstantExpression)exp);
case ExpressionType.Parameter:
return this.VisitParameter((ParameterExpression)exp);
case ExpressionType.MemberAccess:
return this.VisitMemberAccess((MemberExpression)exp);
case ExpressionType.Call:
return this.VisitMethodCall((MethodCallExpression)exp);
case ExpressionType.Lambda:
return this.VisitLambda((LambdaExpression)exp);
case ExpressionType.New:
return this.VisitNew((NewExpression)exp);
case ExpressionType.NewArrayInit:
case ExpressionType.NewArrayBounds:
return this.VisitNewArray((NewArrayExpression)exp);
case ExpressionType.Invoke:
return this.VisitInvocation((InvocationExpression)exp);
case ExpressionType.MemberInit:
return this.VisitMemberInit((MemberInitExpression)exp);
case ExpressionType.ListInit:
return this.VisitListInit((ListInitExpression)exp);
default:
return exp;
}
}
protected virtual MemberBinding VisitBinding(MemberBinding binding) {
switch (binding.BindingType) {
case MemberBindingType.Assignment:
return this.VisitMemberAssignment((MemberAssignment)binding);
case MemberBindingType.MemberBinding:
return this.VisitMemberMemberBinding((MemberMemberBinding)binding);
case MemberBindingType.ListBinding:
return this.VisitMemberListBinding((MemberListBinding)binding);
default:
return binding;
}
}
protected virtual ElementInit VisitElementInitializer(ElementInit initializer) {
ReadOnlyCollection<Expression> arguments = this.VisitExpressionList(initializer.Arguments);
if (arguments != initializer.Arguments) {
return Expression.ElementInit(initializer.AddMethod, arguments);
}
return initializer;
}
protected virtual Expression VisitUnary(UnaryExpression u) {
Expression operand = this.Visit(u.Operand);
if (operand != u.Operand) {
return Expression.MakeUnary(u.NodeType, operand, u.Type, u.Method);
}
return u;
}
protected virtual Expression VisitBinary(BinaryExpression b) {
Expression left = this.Visit(b.Left);
Expression right = this.Visit(b.Right);
Expression conversion = this.Visit(b.Conversion);
if (left != b.Left || right != b.Right || conversion != b.Conversion) {
if (b.NodeType == ExpressionType.Coalesce && b.Conversion != null)
return Expression.Coalesce(left, right, conversion as LambdaExpression);
else
return Expression.MakeBinary(b.NodeType, left, right, b.IsLiftedToNull, b.Method);
}
return b;
}
protected virtual Expression VisitTypeIs(TypeBinaryExpression b) {
Expression expr = this.Visit(b.Expression);
if (expr != b.Expression) {
return Expression.TypeIs(expr, b.TypeOperand);
}
return b;
}
protected virtual Expression VisitConstant(ConstantExpression c) {
return c;
}
protected virtual Expression VisitConditional(ConditionalExpression c) {
Expression test = this.Visit(c.Test);
Expression ifTrue = this.Visit(c.IfTrue);
Expression ifFalse = this.Visit(c.IfFalse);
if (test != c.Test || ifTrue != c.IfTrue || ifFalse != c.IfFalse) {
return Expression.Condition(test, ifTrue, ifFalse);
}
return c;
}
protected virtual Expression VisitParameter(ParameterExpression p) {
return p;
}
protected virtual Expression VisitMemberAccess(MemberExpression m) {
Expression exp = this.Visit(m.Expression);
if (exp != m.Expression) {
return Expression.MakeMemberAccess(exp, m.Member);
}
return m;
}
protected virtual Expression VisitMethodCall(MethodCallExpression m) {
Expression obj = this.Visit(m.Object);
IEnumerable<Expression> args = this.VisitExpressionList(m.Arguments);
if (obj != m.Object || args != m.Arguments) {
return Expression.Call(obj, m.Method, args);
}
return m;
}
protected virtual ReadOnlyCollection<Expression> VisitExpressionList(ReadOnlyCollection<Expression> original) {
List<Expression> list = null;
for (int i = 0, n = original.Count; i < n; i++) {
Expression p = this.Visit(original[i]);
if (list != null) {
list.Add(p);
}
else if (p != original[i]) {
list = new List<Expression>(n);
for (int j = 0; j < i; j++) {
list.Add(original[j]);
}
list.Add(p);
}
}
if (list != null) {
return list.AsReadOnly();
}
return original;
}
protected virtual MemberAssignment VisitMemberAssignment(MemberAssignment assignment) {
Expression e = this.Visit(assignment.Expression);
if (e != assignment.Expression) {
return Expression.Bind(assignment.Member, e);
}
return assignment;
}
protected virtual MemberMemberBinding VisitMemberMemberBinding(MemberMemberBinding binding) {
IEnumerable<MemberBinding> bindings = this.VisitBindingList(binding.Bindings);
if (bindings != binding.Bindings) {
return Expression.MemberBind(binding.Member, bindings);
}
return binding;
}
protected virtual MemberListBinding VisitMemberListBinding(MemberListBinding binding) {
IEnumerable<ElementInit> initializers = this.VisitElementInitializerList(binding.Initializers);
if (initializers != binding.Initializers) {
return Expression.ListBind(binding.Member, initializers);
}
return binding;
}
protected virtual IEnumerable<MemberBinding> VisitBindingList(ReadOnlyCollection<MemberBinding> original) {
List<MemberBinding> list = null;
for (int i = 0, n = original.Count; i < n; i++) {
MemberBinding b = this.VisitBinding(original[i]);
if (list != null) {
list.Add(b);
}
else if (b != original[i]) {
list = new List<MemberBinding>(n);
for (int j = 0; j < i; j++) {
list.Add(original[j]);
}
list.Add(b);
}
}
if (list != null)
return list;
return original;
}
protected virtual IEnumerable<ElementInit> VisitElementInitializerList(ReadOnlyCollection<ElementInit> original) {
List<ElementInit> list = null;
for (int i = 0, n = original.Count; i < n; i++) {
ElementInit init = this.VisitElementInitializer(original[i]);
if (list != null) {
list.Add(init);
}
else if (init != original[i]) {
list = new List<ElementInit>(n);
for (int j = 0; j < i; j++) {
list.Add(original[j]);
}
list.Add(init);
}
}
if (list != null)
return list;
return original;
}
protected virtual Expression VisitLambda(LambdaExpression lambda) {
Expression body = this.Visit(lambda.Body);
if (body != lambda.Body) {
return Expression.Lambda(lambda.Type, body, lambda.Parameters);
}
return lambda;
}
protected virtual NewExpression VisitNew(NewExpression nex) {
IEnumerable<Expression> args = this.VisitExpressionList(nex.Arguments);
if (args != nex.Arguments) {
if (nex.Members != null)
return Expression.New(nex.Constructor, args, nex.Members);
else
return Expression.New(nex.Constructor, args);
}
return nex;
}
protected virtual Expression VisitMemberInit(MemberInitExpression init) {
NewExpression n = this.VisitNew(init.NewExpression);
IEnumerable<MemberBinding> bindings = this.VisitBindingList(init.Bindings);
if (n != init.NewExpression || bindings != init.Bindings) {
return Expression.MemberInit(n, bindings);
}
return init;
}
protected virtual Expression VisitListInit(ListInitExpression init) {
NewExpression n = this.VisitNew(init.NewExpression);
IEnumerable<ElementInit> initializers = this.VisitElementInitializerList(init.Initializers);
if (n != init.NewExpression || initializers != init.Initializers) {
return Expression.ListInit(n, initializers);
}
return init;
}
protected virtual Expression VisitNewArray(NewArrayExpression na) {
IEnumerable<Expression> exprs = this.VisitExpressionList(na.Expressions);
if (exprs != na.Expressions) {
if (na.NodeType == ExpressionType.NewArrayInit) {
return Expression.NewArrayInit(na.Type.GetElementType(), exprs);
}
else {
return Expression.NewArrayBounds(na.Type.GetElementType(), exprs);
}
}
return na;
}
protected virtual Expression VisitInvocation(InvocationExpression iv) {
IEnumerable<Expression> args = this.VisitExpressionList(iv.Arguments);
Expression expr = this.Visit(iv.Expression);
if (args != iv.Arguments || expr != iv.Expression) {
return Expression.Invoke(expr, args);
}
return iv;
}
}
}
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